This SAE Recommended Practice establishes a procedure for determination of vehicle road load force for speeds between 115 km/h and 15 km/h (or between 70 mph and 10 mph). It employs the coastdown method and applies to vehicles designed for on-road operation. The final result is a model of road load force (as a function of speed) during operation on a dry, level road under reference conditions of 20 ¿¿C (68 ¿¿F), 98.21 kPa (29.00 in-Hg), no wind, no precipitation, and the transmission in neutral.